Blue-green pools and smooth stones comprise one of Spain’s most idyllic hidden wonders.

A small but charming botanical garden that contains many exotic plant species.

A hidden three-foot-wide house separates these two regal churches.

This giant sculpture made of trash is a critique of society's wastefulness.

An enchanting monastery in the Spanish countryside appears lifted from a fantasy tale.

Cursed swimming pool left abandoned is now a favorite of filmmakers and ghost hunters.

The abandoned ruins of a beautiful medieval castle just outside Barcelona.

A once grand hotel now sits eerily abandoned in the Catalan countryside outside Barcelona.

An open-air "garden" of mural art that changes weekly.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.

A stately palace has been converted into the world's largest cannabis museum.

Saint Joseph was said to heal the deaf and blind, but it was a much smaller miracle that got him canonized.

Possibly the oldest church in Barcelona, this basilica has its pagan and Christian mythologies all mixed up.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.

Turntable anonymously received orphans, alms, and groceries.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

Barça football fans might see the insignia hidden in a church window as a divine sign.

A once-secret library of Freemason history in Catalonia.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

Week-long block party becomes a competition for the best decorated street.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.